Using custom BUILD and Mu.BUILD in the same class

custom-build.p6

use v6;

class CustomObject {
}

class CustomBuild {
  has $.foo;
  has $.bar;

  submethod BUILD(*%params) {
    $!bar = CustomObject.new;
  }
}

my $object = CustomBuild.new(:foo(17));
# $object.foo should be 17, right?